On Mon, 4 May 2015 17:56:49 +0000 (UTC), John Doe
wrote:

TWIMC...

Assuming the drill needs to be held against the bicycle's bottom bracket
anyway, a non-locking connection turns out to be easy. Lowe's sells 1/2
inch 20 TPI nuts in their specialty drawers (2 for $1.67). That nut fits
on the DeWalt drill spindle. The bicycle bottom bracket tapered spindle
is about 1/2 inch square. So a 1/2 inch drive socket that fits the drill
spindle nut neatly completes the connection.

I might carefully grind a little bit off of the bottom bracket square
tapered spindle and/or maybe the socket drive area so that the 1/2 inch
drive socket slides on a bit further, if I can confidently do that.
Don't want to make it off-center though.

Aha. It sounds like you're trying to lap-in the bearing cones on the
bottom bracket, right?

--
Ed Huntress